Biology subjects

Xu, N.-l.

Publications and source records attributed to Xu, N.-l..

5 recordsLinked to original sources

bioRxiv2026

Marmosets adaptively accumulate dynamic sequential evidence to make decisions

The bounded accumulation model is a dominant theoretical framework to characterize evidence accumulation during decision-making. Using a dynamic sequential tone accumulation (DSTA) task in marmosets, we found that the contribution of late tones to decisions was greater for weaker than for stronger evidence strength-an effect we term evidence-strength-dependent temporal weighting (ETW). Rigorous exclusionary analyses and drift-diffusion modeling further revealed that the bounded accumulation mechanism alone fails to account for this effect, and the online modulation of attentional engagement was identified as the necessary mechanism in addition to the bounded accumulation. Our work thus establishes that attentional engagement is adaptively modulated by evidence strength during complex decision-making.

neuroscience↗

bioRxiv2025

Dendritic computation for rule-based flexible categorization

A hallmark of intelligent behavior is the ability to flexibly respond to external sensory inputs based on dynamically changing rules. A central question is how neurons in the brain implement computations underlying intelligent behaviors. The neocortical pyramidal neurons use their elaborated dendritic arbors to segregate a plethora of inputs and dynamically integrate them--a process known as dendritic computation--which may play important roles in rule-dependent sensory processing. However, evidence directly linking dendritic computation with intelligent cognitive behaviors has been absent. Here we combine two-photon imaging and a rule-switching flexible categorization task in mice to show that a projectome-defined extratelencephalic (ET) cortical layer 5 (L5) neurons in the auditory cortex integrate dendritic rule information and somatic sensory input to enable rule-dependent flexible categorization. The apical dendrite and soma within the same ET neurons exhibit distinct compartmental representations for sensory and rule information, with the soma predominantly encoding sensory information and the dendrites representing inferred task rule. Simultaneous optogenetic dendritic inhibition and two-photon imaging revealed that dendritic rule coding is essential for somatic output of flexible categorization. Our findings indicate that nonlinear dendritic integration of rule and sensory information constitutes a neuronal computational mechanism underlying rule-switching flexible decision-making.

neuroscience↗

bioRxiv2022

Causal contributions to sensory-based decision-making by cell-type specific circuits in the tail striatum

The striatum comprises distinct types of neurons giving rise to the direct and indirect basal ganglia pathways and local circuits. A large amount of work has been focusing on cell-type specific striatal circuits in the context of movement control, proposing several models on their functional roles. But it remains to be elucidated how the cell-type specific striatal circuits contribute to decision-making behavior and whether the existing models apply. Here, we investigate the causal roles of the cell-type specific circuits in the posterior tail of the dorsal striatum (TS) of mice in an auditory-guided decision-making behavior. Transient unilateral activation of the direct- or indirect-pathway striatal spiny projection neurons (dSPNs or iSPNs) both biased decisions in opposite directions. These effects, however, were not due to a direct influence on movement, but was specific to the decision period preceding action execution. Optogenetic inactivation of dSPNs and iSPNs revealed their opposing causal contributions to decisions. At the local circuit level, simutaneous optical recording and manipulation of dSPNs and iSPNs revealed their antagnizing interactions. Inactivation of PV interneurons, a common inhibitory input to both dSPNs and iSPNs, facilitated contraversive choices, supporting a causal contribution of coordinated striatal circuits. Using a neural circuit model, we further demonstrated the computational implemenation of the causal circuit mechanism. Our results indicate that while the causal roles of the cell-type specific striatal circuits in decision-making largely agree with classic models in movement control, they show decision task-related specificity involving local circuit coordination.

neuroscience↗

bioRxiv2022

Somatostatin interneurons in auditory cortex regulate cortical representations and contribute to auditory perception

In the mammalian neocortex, somatostatin (SOM)-expressing GABAergic interneurons serve as a critical circuit component, receiving diverse inputs and targeting various types of cortical neurons. However, their role in perception and cognition remains not well understood. In this study, we employed cell-type specific imaging and perturbation during an auditory perceptual decision task to investigate the contribution of SOM interneurons. Two-photon calcium imaging revealed that auditory cortex (ACx) SOM interneurons exhibit not only frequency-selective responses but also selectivity to categorical choices. Simultaneous optogenetic inactivation and two-photon imaging revealed that SOM interneurons refine the frequency discriminability of auditory cortical neurons and contribute to their selectivity to the categorical decision boundary. Moreover, bilateral chemogenetic inactivation of ACx SOM interneurons impaired behavior-level perceptual categorization. Our findings provide a mechanistic understanding on the functional significance of SOM interneurons in auditory cortical processing and perceptual categorization, linking cell-type specific cortical circuit computations with perceptual functions.

neuroscience↗

bioRxiv2019

A cortico-collicular pathway for motor planning in a memory-dependent perceptual decision task

Survival in a dynamic environment requires animals to plan future actions based on past sensory evidence. However, the neural circuit mechanism underlying this crucial brain function, referred to as motor planning, remains unclear. Here, we employ projection-specific imaging and perturbation methods to investigate the direct pathway linking two key nodes in the motor planning network, the secondary motor cortex (M2) and the midbrain superior colliculus (SC), in mice performing a memory-dependent perceptual decision task. We find dynamic coding of choice information in SC-projecting M2 neurons during motor planning and execution, and disruption of this information by inhibiting M2 terminals in SC selectively impaired decision maintenance. Furthermore, cell-type-specific optogenetic circuit mapping shows that M2 terminals modulate both excitatory and inhibitory SC neurons with balanced synaptic strength. Together, our results reveal the dynamic recruitment of the premotor-collicular pathway as a circuit mechanism for motor planning.

neuroscience↗